Field of the Invention
The present invention relates to a method for producing a suspension board with circuit, to be specific, to a method for producing a suspension board with circuit used in a hard disk drive.
Description of Related Art
In order to improve a degree of freedom in the design of a conductive layer, a suspension board with circuit in which a first base insulating layer, a first conductive layer, a second base insulating layer, and a second conductive layer are sequentially laminated on a metal supporting board has been known. In the suspension board with circuit, for example, while an element-side terminal included in the first conductive layer is electrically connected to a piezo element, a head-side terminal included in the second conductive layer is electrically connected to a magnetic head, and then, the suspension board with circuit is used in a hard disk drive.
It has been proposed that a method for producing the suspension board with circuit includes the following steps (ref: for example, Japanese Unexamined Patent Publication No. 2013-62012):
(1) a step of forming a first base insulating layer having a first opening portion on a metal supporting board,
(2) a step of forming a first conductive layer including a first terminal and a first wire on the first base insulating layer so as to fill the inside of the first opening portion,
(3) a step of forming a second base insulating layer on the first base insulating layer so as to have a second opening portion that exposes a part of the first wire and to cover the remaining first wire, and
(4) a step of forming a second conductive layer including a second terminal and a second wire on the second base insulating layer so as to fill the inside of the second opening portion.